Borax "cotton ball", made up of the hydrous borate minerals ulexite and proberite. Photo from NPS archives.
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Borax basics
Uses for borax
Death Valley borate minerals
Pure boron is never found in nature because of its strong attraction to
oxygen. However, over 100 minerals, called borates, contain boron and oxygen
(borate radical, BO) as important constituents.
There are two basic types of borate minerals. The relatively
rare anhydrous borates,
which have no water incorporated into their structure, are found in metamorphic
and igneous rock. Hydrous borates,
minerals with water incorporated into their structure,
form by the evaporation of mineral-rich water (evaporite minerals) on
desert playas.
Borax is an ingredient in many laundry products. Photo from NPS archives.
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Hydrous borates are relatively soft, white, colorless,
or transparent minerals. Ulexite, colemanite,
and borax are the most common borate minerals
found in Death Valley.
Boron compounds have many household and industrial uses. Boron is a common ingredient of soaps, cleansers, herbicides, soldering fluxes, gasoline antiknock compounds, pharmaceuticals, water softeners, food preservatives, and fire retardants. Boron is also added in the manufacture of glass, pyrex, and porcelain enamels used on kitchen appliances, sinks, bathtubs, stoves, and other products.
Borate Minerals in Death Valley
After H. Majmundar,1985
Mineral name
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Composition
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Sodium borates:
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Borax
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Na2B4O7 10H2O
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Sborgite
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Na2B5O8 5H2O
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Tincalconite
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Na2B4O7 5H2O
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Calcium borates:
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Colemanite
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Ca2B6O11 5H2O
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Ginorite
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Ca2B14O23 8H2O
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Gowerite
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Ca2B6O10 5H2O
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Inyoite
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Ca2B6O11 13H2O
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Meyerhofferite
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Ca2B6O11 7H2O
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Nobleite
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CaB6O11 4H2O
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Priceite
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Ca4B10O19 7H2O
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Magnesium Borates:
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Hungchaoite
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MgB4O7 9H2O
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Inderite
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Mg2B6O11 15H2O
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Kurnakovite
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Mg2B6O11 15H2O
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Macollisterite
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Mg2B12O20 15H2O
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Strontium borate:
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Tunellite
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SrB6O10 4H2O
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Sodium-calcium borates:
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proberite
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NaCaB5O9 5H2O
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Ulexite
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NaCaB5O9 8H2O
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Sodium-magnesium borate:
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Rivadavite
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Na6MgB24O40 22H2O
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Sodium-silicon borate:
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Searlesite
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NaBSi2O6 H2O
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Calcium-magnesium borates:
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Carboborite
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Ca2Mg(CO3)(B2O5) 1OH2O
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Hydroborocite
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CaMgB6O11 6H2O
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Wardsmithite
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Ca5MgB24O42 30H2O
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Calcium-silicon borates:
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Bakerite
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Ca8B10Si6O35 6H2O
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Howlite
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Ca2SiB5O9(OH)5
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Calcium-strontium borate:
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Valkovite
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(Ca,Sr)2B14O23 8H2O
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Natural boric acid:
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Sassolite
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H3BO3
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